[Ultrastructural study of papillomas of the choroid plexus].

The choroid plexus papillomas are rare neoplasms. They constitute about 0.5 per 100 of all intracranial tumors. From a histological point of view they are generally benign tumors. However they give a high mortality rate due to their location near vital structures, the rapid production of intracranial hypertension, and the rich vascularity making risky the surgical treatment.